The purpose of this study is to understand how to improve health care services for HIV-positive women during their pregnancy and after delivery. The study's aim is to compare two different ways of providing antiretroviral therapy for pregnant women with HIV. The study is to be conducted at the Gugulethu Midwife Obstetric Unit (MOU) in Cape Town. There are three phases of the study: Phase 1 is a cross-sectional evaluation of consecutive HIV-infected pregnant women attending their first antenatal clinic visit (n=1600); Phase 2 is an observational cohort that will follow women from Phase 1 who are eligible for ART (n=600) from the second antenatal clinic visit until the first postpartum visit; Phase 3 is a randomized trial of women from Phase 2 who are breastfeeding and will compare two different service models for delivering ART to women after they delivery their babies (n=480). For Phase 3, women who are taking ART will randomly be assigned to either (1) referral to receive ART at the nearest adult clinic at 4-8 weeks after delivery (this is currently how all women receive care in this setting) or (2) to continue to come to the antenatal clinic for ART services until the end of breastfeeding. All women will received the standard local ART services (with identical medications and medical treatment); they are different because some women will stay longer in care at the antenatal clinic. All women participating in Phase 3 will be followed through at least 2 months after they deliver.